Patent GB-346751-A (GB)
Title: Improvements in or relating to the colouration of materials made of or containing organic derivatives of cellulose
IPC: D06P5/15
Filed: 1930-01-09
Abstract: Cellulose esters or ethers, dyeing; printing; azo dyes.-Pattern effects are obtained on materials made of or containing organic cellulose esters or ethers by the local application of reducing discharge or resist preparations incorporating pyrazolone dyes, preferably unsulphonated. Specified reducing agents are formaldehyde sulphoxylates, hydrosulphites, and stannous chloride.  Substances which assist the discharge, e.g. anthraquinone and/or swelling agents for the materials, such as thiocyanates or methyl alcohol, may also be incorporated in the preparations.  The materials may be pretreated with substances having an acid reaction as described in Specification 334,518, [Class 2 (iii), Dyes &c.].  The pyrazolone dyes used may be of the type <FORM:0346751/IV/1> in which R1 is an alkyl radicle, preferably methyl, R2 is an aromatic residue containing one or more azo groups, and R3 is an aromatic radicle.  A table is given showing the shades obtainable in coloured discharges or resists incorporating the following dyes:-aniline, p-chloraniline, p-aminophenol, p-aminodimethylaniline, p-anisidine, cresidine, o-anisidine, p-aminoacetanilide, or 4-dimethylamino-2 - methoxyaniline --> 1 - phenyl - 3 - methyl - 5 - pyrazolone; p-aminoacetanilide, monoacetyl-4 : 41-diaminodiphenylmethane, or monoacetylbenzidine --> 1-phenyl-3-methyl-5-pyrazolone followed by hydrolysis of the acetylamino groups; aniline --> 1-(21-chloro) phenyl-3-methyl-5-pyrazolone or 1-(41-methoxy) phenyl-3-methyl-5-pyrazolone.  The following examples are specified; (1) To obtain a bright yellow pattern on a violet ground a cellulose acetate fabric is dyed with the dyestuff p-nitraniline --> o -oxyethyl-a -naphthylamine, dried, printed with an aqueous paste containing the dyestuff aniline --> 1-phenyl-3-methyl-5-pyrazolone, gum arabic, methylated spirit, and zinc formaldehyde sulphoxylate, steamed, washed, and finished. (2) To obtain a golden yellow pattern on a blue ground a cellulose acetate fabric is dyed with the dyestuff 2 : 4-dinitro-6-methoxyaniline --> the condensation product of epichlorhydrin with a -naphthylamine, dried, printed with an aqueous paste as in (1) containing the dyestuff p-methoxyaniline --> 1-phenyl-3-methyl-5-pyrazolone, and further treated as in (1). (3) To obtain a golden orange pattern on a blue ground a cellulose acetate fabric is dyed with the dyestuff o-anisidine --> a -naphthylamine --> 2 : 3-oxynaphthoic acid, dried, printed with an aqueous paste containing the dyestuff p-aminoacetanilide --> 1-phenyl-3-methyl-5-pyrazolone, gum arabic, methylated spirit, potassium thiocyanate, citric acid, and stannous chloride, steamed, washed, and finished.  Specification 224,681, [Class 2 (iii), Dyes &c.], also is referred to.  4-Dimethylamino-2-methoxyaniline is obtained by methylation of nitroanisidine (NH2 : OCH3 : NO2 = 1 : 3 : 4) followed by reduction of the nitro group.  Monoacetyl-4 : 41-diaminodiphenylmethane is obtained by reduction of one nitro group of 4 : 41-dinitrodiphenylmethane, acetylation of the resulting amino group, and reduction of the second nitro group.